Five different polymerization degrees of cellulose pulps were dissolved in LiCl/DMAc solution, and the cellulose packaging films were prepared by phase transfer technology. The influence of polymerization degree of pulp on mechanical strength and structures of cellulose packaging film was studied. The results showed that tensile strength and elongation at break increased along with the increase of polymerization degree, and the mechanical properties of the films with hardwood were best. The surface roughness decreases following cotton pulp, hardwood pulp to softwood pulp in turn, and the films with hardwood (DP=1286) has dense cross structures.